The present invention relates to a paste-like base having good local retentivity and to preparations containing such bases and an active ingredient.
Hitherto, a very large number of sticky paste preparations have been designed. For example, an ointment comprising an oily ointment base having sodium polyacrylate kneaded therewith, which is intended to stick to the surface of a wet mucous membrane, is known (see U.S. Pat. No. 4,059,686).
When applied to a mucous membrane, although the polymeric material absorbs water and becomes viscous on the wet surface whereby the stickiness increases with a lapse of time, the local retentivity is not sufficient and degradation of the paste starts within a relatively short period of time so that there is not always obtained a satisfactory result from the standpoint of covering and protection on the membrane.
We have now found that a paste comprising certain polyorganosiloxanes and a water-soluble polymeric material not only strongly sticks to a wet surface but is excellent in retentivity such that it is retained there for a long period of time.